Flared brake tube connector

ABSTRACT

A fluid connector assembly comprising (a) a connector body having an inner concave seat having a portion defining a frustoconical surface; (b) an elongate tube having a flared end; and (c) a nut; wherein the connector body is adapted to receive the elongate tube and the nut to form a substantially rigid connection, and wherein the flared end of the tube and the frustoconical surface of the seat are engaged so as to form a fluid seal between the body and the tube; and wherein the flared end has a portion defining an abutment surface having a borderline region in abutment with the frustoconical surface of the inner seat of the body; and wherein the abutment surface of the flared end is a spherical surface.

FIELD OF THE INVENTION

This invention relates to automotive high-pressure brake tube connectorshaving an elongated brake tube with a flared end with its externalabutment surface which is intended to interact with a concave (female)inner seat of connector's body with the purpose to maintain afluid-tight seal of the type used in a motor vehicle to actuate thebraking system.

BACKGROUND TO THE INVENTION

A connector arranges the proper mutual positioning and clamping forcebetween flare and port. The intended for sealing flare's surface (whichis an integrated part of flare's abutment surface) mates with itscounterpart onto the port's seat and creates the seal. Currently, thereare two families of standardized mass-produced brake connectors utilizedin automotive industry.

The first class is based on the interaction of a male type (convex) seatsituated inside connector's port (hole/recess) and extending into it.Accordingly, a female (concave) flare with its inner surface dedicatedfor abutment against the seat with the purpose of forming the fluidseal, is required. This class is represented by the JASO/SAE connectordesign. Its nominal sealing surfaces' shape is a frustum (portion of acone with cut off vertex). Its double inverted flare (funnel or trumpet)has inner (concave) frustum which is intended for sealing onto“external” (convex) frustum (seat) of the port. The design is defined bySAE J533 and JASO F402 standards (which are similar to each other).

The second class of tube flared connectors incorporates the reversedcombination—a female type (concave) seat interacting with a male type(convex) flare. This class is represented by the ISO connector design.It incorporates the flare (bubble) with its external surface dedicatedfor abutment against the seat with the purpose of forming the fluidseal. Nominal shape of its sealing surface is also frustoconical. Thefrustoconical concave seat is an integrated part of the connector port(hole/recess)—there is no any portion extending into the port. The ISOdesign is defined by the SAE standard J1290.

Good and robust connector sealing may be expected only if adequateclamping force is developed onto the contact ring of sufficient sizebetween the sealing surfaces. There is a fundamental shortcoming offrustum to frustum mating. A ring of contact may be expected only if theaxes of both the flare and the port coincide. Otherwise, it is commonthat the result of cone frustum side surfaces crossing (i.e., having ageometry entity which belongs to both frustums) is just a single point.Typically a connector has to provide some degree of robustness, since aring-like shaped initial contact may not be always anticipated. Certainamount of self-adjustment or reasonable sustained deformation duringconnector's securing is expected when initial contact takes place at asingle point. That usually corrects the mutual positions of thecomponents toward development of a ring-like contact area between theflare's and the seat's sealing surfaces. However, there are certainknown limitations of the degree of robustness of current state of theart frustum-to-frustum connectors.

Under certain conditions friction may lock the flare in a misalignedstate against port's seat. Simply put, if the initial contact occurs ona single point, then the flare gets locally squeezed there between thenut and the port. If the effective friction coefficient at that squeezedarea becomes greater than certain threshold then the flare gets locked.Such locking inhibits self-adjustment as mutual motion of the componentsbecomes restricted, and extra torque is not able any more correct poorinitial contact into an uninterrupted ring-like line. At the same timereasonable torque increase may also become not sufficient to provide thedeformation, which becomes required to close the gap between the sealingsurfaces. In this case further torque increase leads to squashing ofjoint's components, which in turn may permanently preclude developmentof the seal.

There are two groups of causes, which are potentially able to lead to asingle point initial contact. First group is related to misalignment ofthe frustums (and this is applicable even if the frustums have idealshapes without deviations/defects). This group of causes is usuallyassociated with an external disturbance. Usually some degree of initialmisalignment is unavoidable and requires some extra torque to overlapthe misalignment by connector's self-adjustment. An external disturbancemay increase initial misalignment or cause difficulty to correct it. Forexample a side force, applied onto the tube in the direction which helpsto increase that initial misalignment, unfavorably changes the balanceof the forces into the connector. Accordingly more extra torque becomesnecessary for additional self-adjustment (sufficient to overlap newbalance of the forces caused by that disturbance). Generally an externaldisturbance consumes certain portion of connector's availableself-adjustment capacity and therefore increases chances of initialsingle point contact and further locking. The second group of causes isrelated to common manufacturing process variations and defects. A singlepoint initial contact between the frustums (alternatively, sort of achain of single points) may also occur because of deviations from theirintended shapes or defects even if the frustums are perfectly aligned.On top of that some local defects (sharp edges, scratches, bulges, chipsetc) at the single point of contact greatly increase effective localfriction. Accordingly those defects may greatly inhibit connectorrobustness leading to significant increase of the probability oflocking.

The following details regarding flare endforming process are useful forunderstanding innate disadvantages of the existing art comparing withthe present invention.

By the design intent ISO flare's cone angle is always less than port'sone. Therefore when ISO flare mates with its port, initial contact issupposed to occur at the small flare frustum diameter (flare's endaround tube's passageway hole). However the very same flare's area ismost vulnerable to deviations. This area is basically the former surfaceof the tube's tip prior to the endforming (a process to form up a flareonto “raw” tubing). Tube's tip is very dependent on quality of thecutting off operation, which is necessary to obtain required tubelength. Plain conditioning of tube's tip surface after the cutting offoperation (brushing, chaffering etc) can not assure ideal circumferencethere and its perpendicularity to tube's axe. The coining (anotherconditioning process, which is well known as effective way to obtainprecise surface) cannot be applied at this area, as no buttress isavailable inside flare's “bubble” during the endforming process.Ambiguity of tube tip surface is also combined with variation of theendforming process. Essentially, current manufacturing practice provideslimited capability to form flare's area around passageway hole of thetube. The SAE standard J1290 also admits such unpredictability. Itsdrawing, which defines ISO flare geometry, notes the area aroundpassageway hole “as formed”. That is serious disadvantage of the ISOflare. This is the most important portion of its sealing surface, whichis intended to be the datum while mating, and which coincides with oneof the less predictable area of the flare. Unavoidable deviations anddefects there directly responsible for interrupted line of the initialcontact and corresponding difficulties to develop the seal.

The other type (SAE/JASO double inverted flare) also has unpredictable“as formed” area around its small frustum diameter. The endformingprocess shapes double inverted flare in such a way that the metal intothe die flows “with the funnel” i.e. toward small frustum diameter. Onlyin case of maximum material condition it is possible to expect theminimum size of small frustum diameter (i.e. on its lower specificationlimit). Otherwise its actual size very depends on actual amount of themetal, which is available within the die. The size also depends on howmuch the tooling is worn out. Thus it is more probable to get biggeractual size of that diameter. Both specifications (SAE and JASO) alsoadmit unpredictability there and stipulate relatively loose tolerancefor this diameter. For the most popular tube sizes of 5/16″ and ¼″ theallowance is 0.75 mm by the SAE standard and 0.70 mm by the JASO, whichis comparable to the nominal size of 1.1 mm of sealing surface seatlength. That is why actual small diameter of flare's frustum can eitherbe greater or smaller than the small diameter of seat's frustum.Accordingly it is possible to have two different ways of mating.

If the actual size of the seat's frustum small diameter is greater thanthe flare's one then initial contact occurs by the seat's top somewhereonto the sealing surface of the flare. That is a preferred way of matingbecause this is the smooth coined sealing inner surface of the flarewhich makes initial contacts with the seat. Accordingly the probabilityof locked misalignment is very low and full-scale connector'sself-adjustment capacity can be expected.

The other (unwanted) way happens if seat's diameter is less than flaresmall frustum diameter. In this case initial contact occurs by theflare's small frustum diameter somewhere onto the seat. Unfortunatelythis is quite probable due to mentioned above limited capability of themanufacturing process. On top of unpredictability of the size of flare'ssmall diameter it is also quite probable to get a defect or deviationthere. And as it was explained before a local defect (sharp edge,scratch, bulge, chip etc) may greatly increase effective local friction.Moreover, lack of available metal during endforming may become“asymmetrical” which in turn can lead to uncompleted circumferencearound actual small diameter area. As the result flare frustum may geteither voided or skewed around its small diameter. Such incompletecircumference may nevertheless become fit to service as actual datumduring mating onto seat's sealing surface. Needless to say, that eachvoid provides a potential leak path, which may or may not be eliminatedby additional torque (deformation). Propensity of a defect combined withinitial single point contact corresponds to high probability of lockedmisalignment. Thus, connector's self-adjustment capability maydeteriorate significantly resulting difficulties to develop the seal.

On top of the fact that small frustum diameter is an unpredictable “asformed” area, it is very difficult to detect deviations of doubleinverted flare there. If the small diameter is not completely formed itis hard to define where exactly it should be measured. It is much morecomplicated than usual to use “inside the tube” generic measurementtools like a caliper on repeatable and reproducible way. Because of costrelated reasons and lack of criteria for thoroughness of that diameter,all available technologies like machine vision systems, laser scanning,X-ray etc are not utilized as an in-process 100% check. Current industrywide practice rather relies on manual sorting on as needed basis.Unfortunately current manufacturing and quality control practices allowrelatively easy escape for defects and deviations at this “as formed”area of JASO/SAE flare.

The problem of relatively easy escape of a quality defect is alsoapplicable to the JASO/SAE seat. It is also difficult to control theshape and the dimensions of such seat and its surrounding area becauseof their “inside the hole” location. On top of that, a convex (male)seat situated inside of its port has many other disadvantages against aconcave (female) integrated into its port one.

The shape of a male seat extending into the port is obviously morecomplex than a female one, and it, thus, requires more steps tomanufacture a male seat. The parts are typically formed using a metalcutting process. The female port according to the present inventionrequires a step to form the hole for the port, a step to cut the threadinto the hole and a last step to finish the bottom portion of the holeto make it suitable for usage as a seat. A male seat, as taught byJASO/SAE, requires all of the above steps plus forming and finishingsteps for the part of the seat extending into the port. Even whenrolling and cold forming technologies may help to combine some of theoperations, the additional body extending into the port invariablyrequires extra steps.

Correspondingly, the tooling to manufacture a female seat port accordingto the present invention is simpler, and, thus, less expensive.

Regarding the quality control of finished products, the female seat portaccording to the present invention is more easily controlled than a maleseat extending into the port. Controlling an internal seat requiresspecial equipment to measure and control both dimension and surfaceroughness internally in the port. Since the female seat is easilyaccessible from the outside, the quality control is simpler.

Despite of its disadvantages the SAE/JASO ports are still widelyutilized because there is a misperception that SAE/JASO flare providesmore robustness to the assembly process than the ISO one. Seemingly easyrepair in fact hides acquired defect (flow reduction) and may lead tountimely part replacement on the field. Since extra torque engagesconnector's self-adjustment, it is a common practice to apply increasedtorque in order to repair connector, if there is a leak. Usage ofexcessive extra torque is virtually undetectable in case of a convex(male) seat. (In case of the ISO flare excessive torque most likelyleads to a crash of the flare and a replacement). A female flare usuallyenvelops seat and eventually translates all the deformations (sustaineddue to excessive torque) onto the seat. Accordingly initial geometry ofsuch male (convex) seat may get changed significantly which may lead toa substantial reduction of the diameter of the passage, which in turnmay cause a considerable decline in flow rate.

The use of a female (concave) seat is superior to the use of a male(convex) seat, and, thus, the use of an external abutment surface of theflare is superior to the use of a flare with internal abutment surface,in terms of sealing capability, flow performance, manufacturingfeasibility and quality control. Accordingly usage of the combination ofa concave (female) seat with an external (convex/male) flare providesbetter method to form a fluid-tight seal comparing to the combination ofa convex (male) seat with a concave (female) flare.

Correspondingly an improved brake tube flare connector based on thecombination of a concave (female) seat with an external (convex/male)flare is needed. Thus, in order to improve sealing robustness byreducing sensitivity to the variations and disturbances, existing maletype flare of the ISO design must targeted as the basis and subject forfurther improvement.

There are two know solutions associated with incorporation of anon-frustoconical shape for the sealing surface. They provide onlypartial improvement to the existing art as only the misalignment relatedproblem (the first mentioned above group of causes) can be resolved. Intheory, a crossing between either two spheres or sphere with cone isalways a circumference. Therefore a circumference as initial contactline between the flare and the seat can be expected even if their axesare misaligned within reasonable span. The first one is U.S. Pat. No.1,894,700, granted Jan. 17, 1933 to Parker, A. L A R. teachingincorporation of zones of sphere for both the flare and the seat. Thesecond one is the US patent application No. 20070194567 published onAug. 23, 2007. It stipulates incorporation of zone of sphere for theseat only which to be utilized with a standard JASO/SAE flare. Bothdesigns are not resilient to the second group of the causes asunavoidable deviations from ideal shape and local surface defects stillmake a single point initial contact possible. Besides, both of thembelong to the first family of the connectors (based on male/convex seatinteracting with female/concave flare). The present invention belongs tothe second family (female/concave seat interacting with male/convexflare) enabling the method to form fluid-tight seal, which is superiorover the first one.

SUMMARY OF THE INVENTION

Accordingly, in one aspect the invention provides a fluid connectorassembly comprising

(a) a connector body having an inner seat having a portion defining aconcave frustoconical surface;

-   -   (b) an elongate tube having a flared end with an external        abutment surface; and    -   (c) a nut;

wherein said connector body is adapted to receive said elongate tube andsaid nut to form a substantially rigid connection, and wherein saidflared end of said tube and said frustoconical surface of said seat areengaged so as to form a fluid seal between said body and said tube; and

wherein said flared end has a portion defining an external abutmentsurface having a borderline region in abutment with said concavefrustoconical surface of said inner seat of said body and wherein saidexternal abutment surface of said flared end is selected from anexternal abutment surface forming at least part of a spherical surfaceand an external abutment surface having a plurality of frustoconicalsurfaces.

Preferably, the invention provides a fluid connector assembly comprising

-   -   (a) a connector body having an inner seat having a portion        defining a concave frustoconical surface;    -   (b) an elongate tube having a flared end with an external        abutment surface; and    -   (c) a nut;

wherein said connector body is adapted to receive said elongate tube andsaid nut to form a substantially rigid connection, and wherein saidflared end of said tube and said frustoconical surface of said seat areengaged so as to form a fluid seal between said body and said tube; and

wherein said flared end has a portion defining an external abutmentsurface having a borderline region in abutment with said concavefrustoconical surface of said inner seat of said body and wherein saidexternal abutment surface of said flared end forms at least part of aspherical surface.

In preferred aspects of the present invention, a run out area, hereinreferred to as a lip, is present in a brake tube flare having anexternal (convex/outer) sealing surface. (By the term “sealing surface”in this specification is meant part of flare's abutment surface, whichis dedicated to mate with the seat with the purpose of formingfluid-tight seal).

The lip is situated between the sealing surface and flare's end aroundthe tube's passageway hole. The lip is bent further away from thesealing surface towards the inside of the tube, i.e. towards the tube'spassageway orifice. The sealing surface and the lip intersect to form,herein termed, a borderline region. The borderline's nominal shape is acircumference.

By the term “borderline region” in this specification is meant acircumferential zone or line of contact between a plurality, i.e. atleast two adjacent surfaces which meet at an angle.

In an embodiment of the invention having a double frustoconical surfacethe borderline region is the circumferential zone of contact between twointegrally formed cones of different slopes relative to thefrustoconical surface portion of the concave seat.

In an embodiment of the invention having a spherical surface, theborderline region is the circumferential zone of contact betweenintegrally formed spherical surface and frustoconical surface ofdifferent slope relative to the frustoconical surface portion of theconcave seat.

Thus, in preferred aspects the invention provides an assembly whereinthe abutment surface of the flared end is selected from a sphericalsurface and a plurality of frustoconical surfaces.

In one further preferred aspect, the invention provides an assemblywherein the abutment surface of the flared end is a spherical surface.

More preferably, the invention provides an assembly wherein the abutmentsurface of the flared end comprises a pair of frustoconical surfacesintegrally formed at the borderline region.

The purpose of the lip is to absorb the unpredictable “as formed” areaat flare's end. The prior art tube tip having known ambiguity of itsgeometry, which combined with limited available capability of themanufacturing endforming process, has been deliberately positioned awayfrom the flare's sealing surface. By its definition, the lip is a “spareand free” run-out area, which absorbs unavoidable variation. Therefore,its shape can be of any configuration suitable to provide acircumference as the nominal shape of the borderline region. Thepreferred nominal shape of the lip is a cone. However, a zone of asphere, or portion of a torus, or a flat ring perpendicular to tube'saxis, or for example a complex combination of all of the above is alsosuitable. In an extreme case, the lip may even become bent “inside” thepassageway hole provided the diameter of the hole is sufficient tosupport the required fluid flow.

The lip is combined either with a cone-shaped sealing surface or asphere-shaped sealing surface. Thus, there are two types of the flareaccording to the invention, i.e. the cone type one with its nominalsealing surface of a cone frustum, or the sphere type with its nominalsealing surface of a zone of sphere. The sealing surface of the conetype of the flare of the present invention preferably has the same angleas existing ISO flares, i.e. of 115±2°. Thus, embodiments of both thecone type and the sphere type flares are such that each fits onto theseat of standard cone port per J1290. However, different sizes andangles can be utilized as long as both the seat and the flare correspondto each other.

When securing a connector having a cone type of the flare of the presentinvention, initial contact with the seat occurs at the borderline regionbetween the lip and the sealing surface. Actual borderline shape isalways a rounded edge (ideally portion of a torus). That difference tothe nominal shape of circumference is due to the fillet radius betweenthe die's lip and sealing surfaces. The borderline region is situatedsomewhat in the middle of the metal flow through the die during theendforming process. Entire available volume of this area gets filledregardless of minimum or maximum material conditions. Accordingly, thesizes are also expected to be exactly as the die commands. Thus, asmooth and predictable rounded edge can be expected there. Hence, theborderline region's rounded edge is not in any way an “as formed”area—contrary to the ISO flare end mentioned hereinabove. Theprobability of leak path occurrence due to a void at the edge isessentially zero. Since datum of the mating (i.e. the rounded edge ofthe borderline region) is smooth and predictable, the probability oflocked misalignment is also essentially zero. Accordingly, full-scaleself-adjusting capacity of the connector is available should amisalignment occur when there is not too much of external disturbance.It is the dramatically absolved from manufacturing process variationpredictable and smooth mating datum, which provides the advantages ofless sensitivity to defects and deviations in the connector, accordingto the present invention.

If the external disturbances exceed certain thresholds, then balance ofthe forces into the connector changes. Thus, the amount of torque, whichwas sufficient to engage the connector's self-adjustment without thedisturbances, may become deficient to provide mutual motion of thecomponents. Accordingly, an external disturbance leads to deteriorationof the connector's self-adjustment capability. In this case, the roundededge may become forced out of alignment with the seat's cone. That, inturn, leads to a single point initial contact, which may or may not becorrected by extra torque. In this case, a spherical shape of sealingsurface helps to maintain circumference shaped initial contact. If muchexternal disturbance is expected, the sphere type flare of the presentinvention is suitable. A sphere intersection with a cone is always acircle. Therefore, in the case of the zone of a sphere intersecting witha cone frustum it is possible to maintain circumferential-shaped initialcontact within certain degrees of their misalignment.

However usage of a sphere-to-cone mating is also subject todisturbances, deviations and variations. Certain amount ofself-adjustment may also be necessary if the actual degree ofmisalignment exceeds expected allowed level. In this case self-adjustinghas to bring the situation (degree of misalignment) down to theacceptable level and only then to utilize the advantages ofsphere-to-cone mating. Therefore, in order to utilize the known propertyof sphere-to-cone mating with respect to resistance to limitedmisalignment, the sensitivity to the second group of causes of spheretype flare of the present invention has to be the same or better incomparison with the cone type one. In extreme situations with excessivemisalignment, initial contact in the sphere type flare may occur at theborderline region between the lip and spherical sealing surface.Depending on the actual shape of the lip, the borderline may take theform of either a rounded edge with a relatively small radius or agradual transition area of a torus with a relatively large radius. Inany case, a smooth and predicted borderline region is critical in thesame way as in the cone type flare of the present invention. If therewere no lip, then a small diameter of the zone of sphere becomes theflare end and, accordingly, becomes “as formed” area absorbing all thevariations and deviations. Thus, the lip in the sphere type flare of thepresent invention is preferred for improved function of a connectorhaving a sphere type flare according to the present invention is, thus,preferred for proper function of a connector having a sphere type flare,according to the present invention.

Each type of flare of the present invention has own niche of usage. Thesphere type flare is prepared for external disturbances. For example, ifa side force is unavoidable then the sphere type embodiment has an edgeover the cone embodiment. Since the sphere type flare is resistant tocertain degree of misalignment, the side force does not need to beoverlapped by self-adjustment, if the misalignment degree is withinexpected operational limits. Thus, less torque is needed in order toseal such a connector because the ring of contact is already there andit only needs to be spread into adequate size. On the other hand, whenexternal disturbances are not significant, the cone type embodiment ofthe flare according to the invention has an edge over the sphere type.No external disturbance usually means no misalignment or misalignment,which is easy to correct by self-adjustment. It is easier to developproper size ring of contact onto an aligned cone-to-cone mating as thegap between the cone surfaces is less than one in sphere-to-cone casesince the sphere surface has a curvature. Further, fewer gaps, in turn,require less securing torque to seal the joint.

In a further aspect, the invention provides an elongate tube having aflared end having a portion defining an abutment surface with aborderline region and selected from the group consisting of a sphericalsurface and a plurality of frustoconical surfaces, wherein said flaredend of said elongate tube is adapted to be received within a connectorbody having a concave frustoconical seat to form a substantially rigidconnection and a seal between said flared end of said elongate tube andsaid frustoconical seat of said connector body.

Preferably, the abutment surface of the flared end is a sphericalsurface combined with frustoconical lip or comprises a pair offrustoconical surfaces integrally formed at the borderline region.

Utilization of a sphere shaped external surface on the tube, which isintended to mate with a concave cone on the seat, provides a new methodof forming a fluid-tight seal.

Thus, according to a further aspect of the present invention, there isprovided a method of forming a substantially-rigid fluidic connection.The method comprises the initial steps of providing a connector bodyhaving a port with a concave conical end portion similar to the conicalseat of a standard ISO port and providing an elongated tube having aflared end with its external abutment surface having its sealing surfaceshaped as a zone of sphere. The next step comprises inserting the tubeinto a connector body, followed by aligning the elongated tube inrelation to the fluidic connector within an angular range and insertinga nut into the connector body so as to forcibly engage the sphere shapedflared end of the elongated tube to the cone end of the seat so as toform a fluidic seal.

In a further aspect of the present invention, the tube flared end isprovided with coining to assure high surface quality and precisionwherein both of the cone or sphere shaped sealing surface and the backface of the flare can be coined. Back face is the part of tube flaredend. Back face provides abutment for the nut embracing and securing thetube in the connector.

By the term “coining” in the art and in this specification is meant aform of precision stamping. It is a typical process to produce coins,medallions and other products that requires the capability to reproducevery fine details. Coining is different from plain stamping in thatenough pressure is utilized to enable plastic flow of the surface of themetal. Typically, a work piece is placed in a confined die and issqueezed during the process. Coining is a well-known and widely utilizedsurface conditioning process that produces a precise and smooth surface.

Thus, in a further aspect, the invention provides an elongate tube ashereinabove defined having at least one a coined flare's surface

Accordingly, the invention provides an elongate tube as hereinabovedefined having either the back face coined or the sealing surface orboth.

The invention still further provides an assembly as hereinabove definedwherein said elongate tube either has its back face coined or thesealing surface or both.

The advantage of coining is to provide avoidance of twisting of the tubewhile being secured in the connector. When the securing torque is beingapplied onto the nut, it rotates or slides over the back face of theflare. Accordingly, a certain amount of torque gets transferred onto theelongated tube, via friction. The friction force between the sealingsurfaces and the strength of the elongated tube in its rotationaldirection equalize that twisting torque. If the friction between theflare's back face and the nut is high enough to transfer the twistingtorque, which is greater than the rotational tube's strength, then thetube's twist becomes highly probable. The friction between the sealingsurfaces is expected to be low, since they have to be smooth, preciseand predictable. The greater the difference between these two frictions,the more probable is to get a twisted tube. Contrariwise, if thefrictions are the same then no twisting torque is transferred onto thetube as the frictions are balanced and cancel that torque. When at leastthe back face is coined, the frictions can be expected to be comparable.Accordingly, the propensity to get the tube twisted during securing ofthe connector in this case is low.

BRIEF DESCRIPTION OF THE DRAWINGS

In order that the invention may be better understood, preferredembodiments will now be described by way of example only, with referenceto the accompanying drawings wherein:

FIG. 1 is a front perspective view of an embodiment of a flare of thepresent invention;

FIG. 2 is a rear perspective view of the embodiment of the flare in FIG.1;

FIG. 3 is a cross sectional view of an embodiment of a cone type flareof the present invention;

FIG. 4 is a cross sectional view of an embodiment of a sphere type flareof the present invention;

FIG. 5 is a semi-cross sectional view, in part, of an embodiment of thecone type flare of the present invention having coined sealing and backface surfaces;

FIG. 6 is a cross sectional view, in part, of an embodiment of thesphere type flare of the present invention having coined sealing andback face surfaces;

FIG. 7 is a cross sectional view of an embodiment of a coupling usingthe sphere type flare of the present invention and a cone port; andwherein the same numerals denote like parts.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

FIGS. 1 and 2 show generally as 10 a flare of use in a brake tubeconnector coupling 100 in FIG. 7 of use in a motor vehicle (not shown).Flare 10 is an integral part of elongate tube 20 at an end thereof, butcan also be formed at both ends of tube 20.

Flare 10 and tube 20 are preferably integrally formed of a single piecea metal material. In alternative embodiments, flare 10 may comprisemultiple pieces or be composed of a non-metal material, either partiallyor entirely, which also may be coupled in a suitable manner, such as forexample, welding, mating threads, and the like to tube 20. Tube 20 ispreferably a prior art brake tube formed of any type of material,homogeneous or otherwise, sufficient for use in automotive brakingapplications or in any other similar application. Tube 20 may beintegrally formed with a source of fluid or device, or also coupled tothe fluid source or device by other methods, whether fixed or removable.Alternatively, tube 20 may be used in a similar application, such as,for example, connecting multiple conduits or branching a single fluidsource to multiple destinations.

Flare 10 comprises a sealing surface 12, a lip area 14, a back face 16and borderline region 18 between sealing surface 12 and lip area 14.Tube 20 also contains a passageway hole 22 throughout the entire lengthof tube 20. Passageway hole 22 is adapted to allow the passage of afluid through a tube coupling arrangement (not shown). Flare 10, tube 20and passageway 22 are preferably concentrically aligned such that theyshare a common central axis.

With reference to FIGS. 3, 4, 5 and 6, passageway hole 22 is defined byinternal surface 24 of tube 20 and internal flare face 26. Internalflare face 26 is situated between internal surface 24 and flare end 28.Flare end 28 is the area where the end of passageway hole 22 meets liparea 14. Internal flare face 26 may take any shape suitable forrealization of the endforming process which produces flare 10, providingthat the size of passageway hole 22 remains of a sufficient size as toallow a required flow of fluid through elongated tube 20.

FIGS. 3, 4, 5 and 6 illustrate different embodiments of the flareaccording to the present invention. FIG. 3 and FIG. 5 each show a conetype flare of the present invention, wherein FIG. 3 shows the cone typeflare without usage of coining. The internal face of flare 10 of FIG. 3is similar to that which exists in a standard ISO “bubble” flare. FIG. 5illustrates a cone type of flare 10 of the present invention with bothsealing surface 12 and back face 16 coined. The shape of internal face26 of FIG. 5 is different from internal face 26 shown in FIG. 3. Theembodiment shown in FIG. 5 is suitable for usage of coining becausewalls 29 of material body 30 are in intimate contact wherein the twolayers of the initial material of tube have been “compressed” togetherduring the late stages of the endforming process. Continuity of materialbody 30 between sealing surface 12 and back face 16 enables coining.Firmness of material body 30 provides a good mutual buttress betweensealing surface 12 and back face 16 during the coining stage of theendforming process. A flat surface is shown to emphasize the impact ofcoining on flare's back face 16 in Figures. Sealing surface 12 of conetype of flare 10 of the present invention preferably has the same angleof 115°±2° as an ISO flare. Therefore, preferred embodiments of the conetype of flare 10 can fit into the seat of a standard cone port perJ1290. However, different sizes and angles can also be utilized as longas both the seat and the flare correspond to each other.

FIGS. 4 and 6 show preferred embodiments of a sphere type flare 10according to the present invention. The embodiment shown in FIG. 4 doesnot utilize coining. The embodiment shown in FIG. 6 has sealing surface12 and back face 16 coined. Internal flare face 26 shown in FIGS. 4 and6 are analogously different in the same way as was explained hereinabovein respect of FIGS. 3 and 5. The embodiment shown in FIG. 6 is suitablefor coining incorporation as the material body 30 has continuity fromsealing surface 12 to back face 16. Upper dashed line 32 at the righthalf of the cross-section describes a double layer of raw tube material30. To emphasize the impact of coining onto back face 16 it is shownflat.

Since FIG. 6 shows an embodiment of the sphere type of flare 10,according to the invention, the cross section line representing sealingsurface 12 is a portion of a large circle. The lower thin dashed line 33in FIG. 6 denotes a cone type sealing surface and aims to helprecognition of the difference between the sphere and the cone types ofthe flare of the present invention.

It should be noted that the shape of lip area 14 is similar in FIGS. 3and 5, but different from lip area 14 shown in FIG. 4 and FIG. 6. Thisis to illustrate the fact that preferred embodiments of the lip can takemany suitable shapes. A shape is suitable for the lip area 14 as long asit can support a circumference as the nominal shape of the borderlineregion with sealing surface 12. The lip area 14 can take the shape of azone of a sphere, or portion of a torus, or a flat ring perpendicular tothe axis of the tube; or for example, a complex combination of all ofthe above can be suitable. Lip 14 may also be bent “inside” passagewayhole 22 as it shown in FIG. 4 providing the passageway of the holeremains sufficient to support required flow.

With reference now to FIG. 7, this shows a preferred embodiment of themethod of forming a substantially rigid fluidic connection using asphere type flare 10 of the present invention. The preferred embodimentof a coupling is a threaded connector having a body 40 adapted toreceive elongated tube 20, such that the spherical sealing surface 12 offlare 10 and concave cone seat 42 of body 40 are engaged in a sealingrelationship. Connector body 40 contains an internal thread 44. A nut 50comprises a central bore 52, a threaded exterior portion 54 and abuttingface 56 and a head portion 58. Central bore 52 passes entirely throughnut 50 and is intended to accommodate elongated tube 20. Threadedexterior portion 54 and central bore 52 are concentric, and co-axial insharing a common central axis. Head portion 58 is adapted to be drivenby a fastening tool to allow the securing of connector 40. Both nut 50and connector body 40 are preferably composed of a homogenous metallicmaterial, but may also be composed of multiply pieces or anothermaterial, such as a plastics material. The surfaces of abutting face 56and back face 16 are shown flat but could be of any suitable shape.

Nut 50 functions to hold sealing surface 12 of elongated tube 20 insealing relationship with concave seat 42. Such holding is achieved viaengagement of threaded portion 54 of nut 50 and body thread 44, which isenforced by an external torque applied onto head portion 58, which inturn forces contact between abutting face 56 and back face 16. Theinteraction defined by the conical shape of seat 42 and the zone of asphere of sealing surface 12 provides for circumscribing, i.e.ring-shaped contact, through a range of annular alignments, therebylimiting leak path occurrence.

Modifications to embodiments of the invention described in the foregoingare possible without departing from the scope of the invention asdefined by the accompanying clams. Expressions such as “including”,“comprising”, “incorporating”, “consisting of”, “have”, “is” used todescribe and claim the present invention are intended to be construed ina non-exclusive manner, namely allowing for items, components, orelements not explicitly described also to be present. Reference to thesingular is also to be construed to relate to the plural.

Although this disclosure has described and illustrated certain preferredembodiments of the invention, it is to be understood that the inventionis not restricted to those particular embodiments. Rather, the inventionincludes all embodiments, which are functional or mechanical equivalenceof the specific embodiments and features that have been described andillustrated.

1. A fluid connector assembly comprising (a) a connector body having aninner seat having a portion defining a concave frustoconical surface;(b) an elongate tube having a flared end with an external abutmentsurface; and (c) a nut; wherein said connector body is adapted toreceive said elongate tube and said nut to form a substantially rigidconnection, and wherein said flared end of said tube and saidfrustoconical surface of said seat are engaged so as to form a fluidseal between said body and said tube; and wherein said flared end has aportion defining an external abutment surface having a borderline regionin abutment with said concave frustoconical surface of said inner seatof said body; and wherein said external abutment surface of said flaredend is selected from an external abutment surface forming at least partof a spherical surface and an external abutment surface having aplurality of frustoconical surfaces.
 2. A fluid connector assembly asclaimed in claim 1 comprising (a) a connector body having an inner seathaving a portion defining a concave frustoconical surface; (b) anelongate tube having a flared end with an external abutment surface; and(c) a nut; wherein said connector body is adapted to receive saidelongate tube and said nut to form a substantially rigid connection, andwherein said flared end of said tube and said frustoconical surface ofsaid seat are engaged so as to form a fluid seal between said body andsaid tube; and wherein said flared end has a portion defining anexternal abutment surface having a borderline region in abutment withsaid concave frustoconical surface of said inner seat of said body; andwherein said external abutment surface of said flared end forms at leastpart of a spherical surface.
 3. An assembly as claimed in claim 1,wherein the borderline region is a circumferential zone of initialcontact between the external abutment surface and the concavefrustoconical surface.
 4. An assembly as claimed in claim 1, wherein theexternal abutment surface and the concave frustoconical surface meet atan angle.
 5. An assembly as claimed in claim 3, wherein the externalabutment surface and the concave frustoconical surface meet at an angle.6. An assembly as claimed in claim 1, wherein said external abutmentsurface of said flared end comprises a pair of frustoconical surfacesintegrally formed at said borderline region situated in between of saidfrustoconical surfaces.
 7. An assembly as claimed in claim 3, whereinsaid external abutment surface of said flared end comprises a pair offrustoconical surfaces integrally formed at said borderline regionsituated in between of said frustoconical surfaces.
 8. An assembly asclaimed in claim 4, wherein said external abutment surface of saidflared end comprises a pair of frustoconical surfaces integrally formedat said borderline region situated in between of said frustoconicalsurfaces.
 9. An assembly as claimed in claim 5, wherein said externalabutment surface of said flared end comprises a pair of frustoconicalsurfaces integrally formed at said borderline region situated in betweenof said frustoconical surfaces.
 10. An assembly as claimed in claim 1,wherein said external abutment surface of said flared end comprises partof a spherical surface integrally formed at said borderline region witha frustoconical surface.
 11. An assembly as claimed in claim 3, whereinsaid external abutment surface of said flared end comprises part of aspherical surface integrally formed at said borderline region with afrustoconical surface.
 12. An assembly as claimed in claim 4, whereinsaid external abutment surface of said flared end comprises part of aspherical surface integrally formed at said borderline region with afrustoconical surface.
 13. An elongate tube having a flared end having aportion defining an external abutment surface with a borderline region,wherein the external abutment surface comprises at least a part of aspherical surface, and wherein said flared end of said elongate tube isadapted to be received within a connector body having a concavefrustoconical seat to form a substantially rigid connection and a sealbetween said flared end of said elongate tube and said frustoconicalseat of said connector body.
 14. An elongate tube as claimed in claim13, wherein said external abutment surface of said flared end comprisespart of a spherical surface integrally formed at said borderline regionwith a frustoconical surface.
 15. An elongate tube as claimed in claim13, wherein said external abutment surface of said flared end comprisesa pair of frustoconical surfaces integrally formed at said borderlineregion situated in between of said frustoconical surfaces.
 16. Anelongate tube as claimed in claim 13, wherein the flare of said tube hasat least one a coined surface.
 17. An elongate tube as claimed in claim16, wherein the coined surface is selected from a sealing surface and aback face of the flare.
 18. An assembly as claimed in claim 1, whereinthe flare of said elongate tube has at least one coined surface.
 19. Anassembly as claimed in claim 18, wherein the coined surface is selectedfrom a sealing surface and a back face of the flare.
 20. A method offorming a fluid seal using an assembly as claimed in claim 1.